There is hardly any game in with Swedish subtitles or voice acting, except those educational games.
So for that reason I choose English, because that is what I know the most of. I could also choose Spanish, which I have done a few times, but that almost never happens.
Even if most games were in Swedish, I would not choose it because as The1 said, Swedish does sound too serious. I can't imagine playing a game like Ace Attorney or Pokémon in Swedish. Although it does sound quite funny in the anime.
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